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#include "leetcode.h"
class Solution {
public:
int maxSumSubmatrix(vector<vector<int>> &matrix, int k) {
int ans = INT_MIN, rows = matrix.size(), cols = matrix[0].size();
for (int l = 0; l < cols; ++l) {
vector<int> sums(rows);
for (int r = l; r < cols; ++r) {
int pMin = 0, pMax = INT_MIN;
for (int i = 0; i < rows; ++i) {
sums[i] += matrix[i][r];
pMin = max(pMin + sums[i], sums[i]);
pMax = max(pMax, pMin);
}
if (pMax <= k) {
ans = max(ans, pMax);
continue;
}
set<int> s = {0};
int runSum = 0;
for (int sum : sums) {
runSum += sum;
auto it = s.lower_bound(runSum - k);
if (it != end(s))
ans = max(ans, runSum - *it);
s.insert(runSum);
}
}
}
return ans;
}
};
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